Answer:
$65
Step-by-step explanation:
Let's add up the flat rate and the cost of four tires:
flat rate + 4($122.57/tire) = $555.28
We are to solve for "flat rate." First, multiply out 4($122.57/tire), obtaining a tire cost of $490.28 total. Subtracting this tire cost from the $555.28 Janette paid the shop, we get "flat rate" = $555.28 - $490.28, or $65.
Thus, the installation charge ("flat rate") must have been $65.
